Skip to main content Accessibility help
×
Home
Hostname: page-component-7f7b94f6bd-8p2w5 Total loading time: 0.191 Render date: 2022-06-30T07:45:48.589Z Has data issue: true Feature Flags: { "shouldUseShareProductTool": true, "shouldUseHypothesis": true, "isUnsiloEnabled": true, "useRatesEcommerce": false, "useNewApi": true } hasContentIssue true

Some genetic tests on asymmetry of sternopleural chaeta number in Drosophila

Published online by Cambridge University Press:  14 April 2009

E. C. R. Reeve
Affiliation:
Agricultural Research Council Unit of Animal Genetics, Institute of Animal Genetics, Edinburgh, 9
Rights & Permissions[Opens in a new window]

Extract

HTML view is not available for this content. However, as you have access to this content, a full PDF is available via the ‘Save PDF’ action button.

1. Published data suggest that mean left-right asymmetry in number of sternopleural bristles of D. melanogaster declines when inbred lines are crossed, while the corresponding variance for sternite bristles remains unchanged. Some genetic tests were undertaken to analyse this difference in behaviour of the two characters.

2. A progeny test on a wild stock showed that a small amount of genetic variance in sternopleural asymmetry was present, equivalent to about 2% of the total phenotypic variance.

3. It was possible to increase and decrease the level of sternopleural asymmetry in two wild stocks by selection. These experiments gave an estimated heritability of some 2–3%, in close agreement with the progeny test. Change in asymmetry did not necessarily lead to a change in mean count.

4. Homozygous lines, consisting of individual third chromosomes from the Renfrew wild stock made homozygous in an inbred line genetic background, were intercrossed, and the average indices for a number of characters of eight inter crosses involving eight lines were compared with their mid-parent averages. Thorax length was 2% greater and its variance 32% less in the crosses; total sternopleural count and its variance did not change significantly, but the asymmetry variance declined by 18%. In contrast, the corresponding asymmetry or independent variance for numbers of sternite bristles was 6% higher in the crosses, although the total sternite count and its variance did not change. These results fit in with previous work.

5. Tests on a similar set of homozygous lines in which the third chromosomes came from the SP wild stock, and on some long inbred lines from the Pacific wild stock, gave discordant results. Of eight SP lines examined, four were homozygous for a gene polychaetoid, and four were homozygous for a genetic effect causing sockets without bristles to occur among the sternopleurals. Both types had much greater sternopleural variance and asymmetry than the Renfrew lines, and both indices declined sharply in intercrosses leaving these genetic effects heterozygous, but neither declined if they were left homozygous in the crosses. Similarly high sternopleural variances were found in the Pacific lines, but only the total variance declined in males and only the asymmetry variance declined in the females, when they were intercrossed. All the four Pacific lines tested appeared to be homozygous for a genetic effect which caused a variable number of dorso-central and scutellar bristles to be replaced by sockets without bristles, and an occasional extra scutellar bristle to appear. This effect was also probably responsible for the high sternopleural variances.

6. Males of the Pacific inbred lines and intercrosses were compared when reared on the normal live medium and on a synthetic diet in reduced concentration, which reduced body-size by 23% (thorax area). The inbred lines were reduced more than the F1's in total sternopleural count and its variance, but the F1's were reduced more in sternopleural asymmetry, by the restricted diet.

7. The problems of interpreting these experiments, in view of our ignorance of the biological functions and attributes of the sternopleural and sternite bristles, are discussed. It is concluded that we have no basis yet for deciding whether sternopleural bristle number is of adaptive significance, but this is considered improbable.

8. The experimental evidence suggests that sternopleural asymmetry cannot be considered a measure of general developmental stability, particularly as the level of asymmetry can be reduced by selection well below that of typical wild stocks.

9. The scaling problems arising when the mean asymmetry of lines with different mean counts are to be compared, are examined, and it is suggested that the ratio of asymmetry to total count does not eliminate scale effects.

10. Developmental and anatomical differences between the sternopleural and sternite bristles suggest a possible reason why they behave differently when inbred lines are intercrossed.

Type
Research Article
Copyright
Copyright © Cambridge University Press 1960

References

Auerbach, C. (1936). The development of the legs, wings and halteres in wild type and some mutant strains of Drosophila melanogaster. Trans. roy. Soc. Edinb. 58, 787815.Google Scholar
Clayton, G. A., Morris, J. A. & Robertson, A. (1957). An experimental check on quantitative genetical theory. I. The short-term responses to selection. J. Genet. 55, 131151.CrossRefGoogle Scholar
Falconer, D. S. (1954). Asymmetrical responses in selection experiments. Symposium on genetics of population structure. Int. Un. biol. Sci., Naples, Ser. B, No. 15, 1641.Google Scholar
Harrison, B. J. (1954). Selection for differences in chaeta number between the fifth and fourth sternites of D. Melanogaster. Drosophila Inform. Serv., 28, 122123.Google Scholar
Lerner, I. M. (1954). Genetic Homeostasis. Oliver & Boyd, Edinburgh.Google Scholar
Mather, K. (1953). Genetical control of stability in development. Heredity, 7, 297336.CrossRefGoogle Scholar
Reeve, E. C. R. & Robertson, F. W. (1953 a). Studies in quantitative inheritance. II. Analysis of a strain of Drosophila selected for long wings. J. Genet. 51, 276316.CrossRefGoogle Scholar
Reeve, E. C. R. & Robertson, F. W. (1953). Analysis of environmental variability in quantitative inheritance. Nature, Lond., 171, 874876.CrossRefGoogle ScholarPubMed
Reeve, E. C. R. & Robertson, F. W. (1954). Studies in quantitative inheritance. VI. Sternite chaeta number in Drosophila: a metameric quantitative character. Z. indukt. Abstamm.- u. VererbLehre, 86, 269288.Google ScholarPubMed
Robertson, F. W. (1957). Studies in quantitative inheritance. X. Genetic variation of ovary size in Drosophila. J. Genet. 55, 410427.CrossRefGoogle Scholar
Robertson, F. W. & Reeve, E. C. R. (1955). Studies in quantitative inheritance. VIII. Further analysis of heterosis in crosses between inbred lines of Drosophila melanogaster. Z. indukt. Abstamm.- u. VererbLehre, 86, 439458.Google ScholarPubMed
Sang, J. H. (1956). The quantitative nutritional requirements of Drosophila melanogaster. J. exp. Biol. 33, 4572.Google Scholar
Thoday, J. M. (1958). Homeostasis in a selection experiment. Heredity, 12, 401415.CrossRefGoogle Scholar
Waddington, C. H. (1953). Epigenetics and evolution. Symp. Soc. exp. Biol. 7, 186199.Google Scholar
Waddington, C. H., Graber, H. & Woolf, B. (1957). Iso-alleles and response to selection. J. Genet. 55, 246250.CrossRefGoogle Scholar
Wright, S. (1952). The genetics of quantitative variability. In Quantitative Inheritance, eds. Reeve, E. C. R. & Waddington, C. H., pp. 541. Her Majesty's Stationery Office, London.Google Scholar
You have Access

Save article to Kindle

To save this article to your Kindle, first ensure coreplatform@cambridge.org is added to your Approved Personal Document E-mail List under your Personal Document Settings on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part of your Kindle email address below. Find out more about saving to your Kindle.

Note you can select to save to either the @free.kindle.com or @kindle.com variations. ‘@free.kindle.com’ emails are free but can only be saved to your device when it is connected to wi-fi. ‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.

Find out more about the Kindle Personal Document Service.

Some genetic tests on asymmetry of sternopleural chaeta number in Drosophila
Available formats
×

Save article to Dropbox

To save this article to your Dropbox account, please select one or more formats and confirm that you agree to abide by our usage policies. If this is the first time you used this feature, you will be asked to authorise Cambridge Core to connect with your Dropbox account. Find out more about saving content to Dropbox.

Some genetic tests on asymmetry of sternopleural chaeta number in Drosophila
Available formats
×

Save article to Google Drive

To save this article to your Google Drive account, please select one or more formats and confirm that you agree to abide by our usage policies. If this is the first time you used this feature, you will be asked to authorise Cambridge Core to connect with your Google Drive account. Find out more about saving content to Google Drive.

Some genetic tests on asymmetry of sternopleural chaeta number in Drosophila
Available formats
×
×

Reply to: Submit a response

Please enter your response.

Your details

Please enter a valid email address.

Conflicting interests

Do you have any conflicting interests? *